Drive drums, direction-reversal drums, deflector drums, and drum coverings for these are disclosed by way of example in DE 1 781 214, DD 290 166 A5, DD 290 165 A5, or DD 267 474 A1.
The drum coverings for the drive drum and/or directional-reversal drum and/or deflector drums, these being important components of a conveyor installation, are mostly composed as described by way of example in DD 267 474 A1 of a rubber mixture comprising at least one rubber component or one rubber-component blend, at least one crosslinking agent or one crosslinking system, comprising a crosslinking agent and an accelerator, and also mostly other mixture ingredients, in particular at least one filler and/or at least one processing aid and/or at least one antioxidant and/or at least one plasticizer and/or other additional substances (for example, fibers, color pigments). The vulcanization of the rubber mixture gives the drum coverings appropriate resilient properties.
The drum coverings are usually adhesive-bonded at low temperatures on the individual drums (drive drum, direction-reversal drum, deflector drum, loadbearing rollers, et cetera), and serve to improve force transmission to the conveyor belt, since the rubberization mostly applied on the drum, termed drum covering, reduces slip between rubber and metal. Direct contact is thus achieved between the drum covering made of rubber and a mostly rubberized outer sheet of the conveyor belt. By way of example, the force exerted at the circumference of the drive drum has to be sufficiently high to be capable of achieving frictional drive of the pretensioned loaded conveyor belt. The covering of the drums in belt-conveyor installations therefore has a decisive effect on the maximal transferable torque, and on the lifetime of the belt.
The implication of the abovementioned “slip” is that optimal running of the conveyor belt is prevented, or that, because material to be conveyed penetrates between the drum surface and the conveyor belt, the drum and the conveyor belt can be damaged.